/*
 * ffmpeg filter configuration
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "ffmpeg.h"

#include "libavfilter/avfilter.h"
#include "libavfilter/avfiltergraph.h"
#include "libavfilter/buffersink.h"

#include "libavutil/audioconvert.h"
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/bprint.h"
#include "libavutil/pixdesc.h"
#include "libavutil/pixfmt.h"
#include "libavutil/imgutils.h"
#include "libavutil/samplefmt.h"

enum AVPixelFormat choose_pixel_fmt( AVStream *st, AVCodec *codec, enum AVPixelFormat target )
{
    if ( codec && codec->pix_fmts )
    {
        const enum AVPixelFormat *p = codec->pix_fmts;
        const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get( target );
        int has_alpha = desc ? desc->nb_components % 2 == 0 : 0;
        enum AVPixelFormat best = AV_PIX_FMT_NONE;

        if ( st->codec->strict_std_compliance <= FF_COMPLIANCE_UNOFFICIAL )
        {
            if ( st->codec->codec_id == AV_CODEC_ID_MJPEG )
            {
                enum AVPixelFormat px[] = {AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_NONE };
                p = ( const enum AVPixelFormat* )px;
            }
            else if ( st->codec->codec_id == AV_CODEC_ID_LJPEG )
            {
                enum AVPixelFormat px1[] = {AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUV420P,
                                            AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV444P, AV_PIX_FMT_BGRA, AV_PIX_FMT_NONE
                                           };
                p = ( const enum AVPixelFormat* )px1;
            }
        }

        for ( ; *p != AV_PIX_FMT_NONE; p++ )
        {
            best = avcodec_find_best_pix_fmt_of_2( best, *p, target, has_alpha, NULL );

            if ( *p == target )
                break;
        }

        if ( *p == AV_PIX_FMT_NONE )
        {
            if ( target != AV_PIX_FMT_NONE )
                av_log( NULL, AV_LOG_WARNING,
                        "Incompatible pixel format '%s' for codec '%s', auto-selecting format '%s'\n",
                        av_get_pix_fmt_name( target ),
                        codec->name,
                        av_get_pix_fmt_name( best ) );

            return best;
        }
    }

    return target;
}

void choose_sample_fmt( AVStream *st, AVCodec *codec )
{
    if ( codec && codec->sample_fmts )
    {
        const enum AVSampleFormat *p = codec->sample_fmts;

        for ( ; *p != -1; p++ )
        {
            if ( *p == st->codec->sample_fmt )
                break;
        }

        if ( *p == -1 )
        {
            if ( ( codec->capabilities & CODEC_CAP_LOSSLESS ) && av_get_sample_fmt_name( st->codec->sample_fmt ) > av_get_sample_fmt_name( codec->sample_fmts[0] ) )
                av_log( NULL, AV_LOG_ERROR, "Conversion will not be lossless.\n" );

            if ( av_get_sample_fmt_name( st->codec->sample_fmt ) )
                av_log( NULL, AV_LOG_WARNING,
                        "Incompatible sample format '%s' for codec '%s', auto-selecting format '%s'\n",
                        av_get_sample_fmt_name( st->codec->sample_fmt ),
                        codec->name,
                        av_get_sample_fmt_name( codec->sample_fmts[0] ) );

            st->codec->sample_fmt = codec->sample_fmts[0];
        }
    }
}

static char *choose_pix_fmts( OutputStream *ost )
{
    if ( ost->keep_pix_fmt )
    {
        if ( ost->filter )
            avfilter_graph_set_auto_convert( ost->filter->graph->graph,
                                             AVFILTER_AUTO_CONVERT_NONE );

        if ( ost->st->codec->pix_fmt == AV_PIX_FMT_NONE )
            return NULL;

        return av_strdup( av_get_pix_fmt_name( ost->st->codec->pix_fmt ) );
    }

    if ( ost->st->codec->pix_fmt != AV_PIX_FMT_NONE )
    {
        return av_strdup( av_get_pix_fmt_name( choose_pixel_fmt( ost->st, ost->enc, ost->st->codec->pix_fmt ) ) );
    }
    else if ( ost->enc && ost->enc->pix_fmts )
    {
        const enum AVPixelFormat *p;
        AVIOContext *s = NULL;
        uint8_t *ret;
        int len;

        if ( avio_open_dyn_buf( &s ) < 0 )
            exit( 1 );

        p = ost->enc->pix_fmts;

        if ( ost->st->codec->strict_std_compliance <= FF_COMPLIANCE_UNOFFICIAL )
        {
            if ( ost->st->codec->codec_id == AV_CODEC_ID_MJPEG )
            {
                enum AVPixelFormat px[] = { AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_NONE };
                p = ( const enum AVPixelFormat* )px;
            }
            else if ( ost->st->codec->codec_id == AV_CODEC_ID_LJPEG )
            {
                enum AVPixelFormat px1[] = {AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUV420P,
                                            AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV444P, AV_PIX_FMT_BGRA, AV_PIX_FMT_NONE
                                           };
                p = ( const enum AVPixelFormat* )px1;
            }
        }

        for ( ; *p != AV_PIX_FMT_NONE; p++ )
        {
            const char *name = av_get_pix_fmt_name( *p );
            avio_printf( s, "%s:", name );
        }

        len = avio_close_dyn_buf( s, &ret );
        ret[len - 1] = 0;
        return ret;
    }
    else
        return NULL;
}

/* Define a function for building a string containing a list of
 * allowed formats. */
#define DEF_CHOOSE_FORMAT(type, var, supported_list, none, get_name, separator)\
static char *choose_ ## var ## s(OutputStream *ost)                            \
{                                                                              \
    if (ost->st->codec->var != none) {                                         \
        get_name(ost->st->codec->var);                                         \
        return av_strdup(name);                                                \
    } else if (ost->enc->supported_list) {                                     \
        const type *p;                                                         \
        AVIOContext *s = NULL;                                                 \
        uint8_t *ret;                                                          \
        int len;                                                               \
                                                                               \
        if (avio_open_dyn_buf(&s) < 0)                                         \
            exit(1);                                                           \
                                                                               \
        for (p = ost->enc->supported_list; *p != none; p++) {                  \
            get_name(*p);                                                      \
            avio_printf(s, "%s" separator, name);                              \
        }                                                                      \
        len = avio_close_dyn_buf(s, &ret);                                     \
        ret[len - 1] = 0;                                                      \
        return ret;                                                            \
    } else                                                                     \
        return NULL;                                                           \
}

// DEF_CHOOSE_FORMAT(enum AVPixelFormat, pix_fmt, pix_fmts, AV_PIX_FMT_NONE,
//                   GET_PIX_FMT_NAME, ":")

DEF_CHOOSE_FORMAT( enum AVSampleFormat, sample_fmt, sample_fmts,
                   AV_SAMPLE_FMT_NONE, GET_SAMPLE_FMT_NAME, "," )

DEF_CHOOSE_FORMAT( int, sample_rate, supported_samplerates, 0,
                   GET_SAMPLE_RATE_NAME, "," )

DEF_CHOOSE_FORMAT( uint64_t, channel_layout, channel_layouts, 0,
                   GET_CH_LAYOUT_NAME, "," )

FilterGraph *init_simple_filtergraph( InputStream *ist, OutputStream *ost )
{
    FilterGraph *fg = av_mallocz( sizeof( *fg ) );

    if ( !fg )
        exit( 1 );

    fg->index = nb_filtergraphs;

    fg->outputs = grow_array( fg->outputs, sizeof( *fg->outputs ), &fg->nb_outputs,
                              fg->nb_outputs + 1 );

    if ( !( fg->outputs[0] = av_mallocz( sizeof( *fg->outputs[0] ) ) ) )
        exit( 1 );

    fg->outputs[0]->ost   = ost;
    fg->outputs[0]->graph = fg;

    ost->filter = fg->outputs[0];

    fg->inputs = grow_array( fg->inputs, sizeof( *fg->inputs ), &fg->nb_inputs,
                             fg->nb_inputs + 1 );

    if ( !( fg->inputs[0] = av_mallocz( sizeof( *fg->inputs[0] ) ) ) )
        exit( 1 );

    fg->inputs[0]->ist   = ist;
    fg->inputs[0]->graph = fg;

    ist->filters = grow_array( ist->filters, sizeof( *ist->filters ),
                               &ist->nb_filters, ist->nb_filters + 1 );
    ist->filters[ist->nb_filters - 1] = fg->inputs[0];

    filtergraphs = grow_array( filtergraphs, sizeof( *filtergraphs ),
                               &nb_filtergraphs, nb_filtergraphs + 1 );
    filtergraphs[nb_filtergraphs - 1] = fg;

    return fg;
}

static void init_input_filter( FilterGraph *fg, AVFilterInOut *in )
{
    InputStream *ist = NULL;
    enum AVMediaType type = avfilter_pad_get_type( in->filter_ctx->input_pads, in->pad_idx );
    int i;

    // TODO: support other filter types
    if ( type != AVMEDIA_TYPE_VIDEO && type != AVMEDIA_TYPE_AUDIO )
    {
        av_log( NULL, AV_LOG_FATAL, "Only video and audio filters supported "
                "currently.\n" );
        exit( 1 );
    }

    if ( in->name )
    {
        AVFormatContext *s;
        AVStream       *st = NULL;
        char *p;
        int file_idx = strtol( in->name, &p, 0 );

        if ( file_idx < 0 || file_idx >= nb_input_files )
        {
            av_log( NULL, AV_LOG_FATAL, "Invalid file index %d in filtergraph description %s.\n",
                    file_idx, fg->graph_desc );
            exit( 1 );
        }

        s = input_files[file_idx]->ctx;

        for ( i = 0; i < s->nb_streams; i++ )
        {
            enum AVMediaType stream_type = s->streams[i]->codec->codec_type;

            if ( stream_type != type &&
                    !( stream_type == AVMEDIA_TYPE_SUBTITLE &&
                       type == AVMEDIA_TYPE_VIDEO /* sub2video hack */ ) )
                continue;

            if ( check_stream_specifier( s, s->streams[i], *p == ':' ? p + 1 : p ) == 1 )
            {
                st = s->streams[i];
                break;
            }
        }

        if ( !st )
        {
            av_log( NULL, AV_LOG_FATAL, "Stream specifier '%s' in filtergraph description %s "
                    "matches no streams.\n", p, fg->graph_desc );
            exit( 1 );
        }

        ist = input_streams[input_files[file_idx]->ist_index + st->index];
    }
    else
    {
        /* find the first unused stream of corresponding type */
        for ( i = 0; i < nb_input_streams; i++ )
        {
            ist = input_streams[i];

            if ( ist->st->codec->codec_type == type && ist->discard )
                break;
        }

        if ( i == nb_input_streams )
        {
            av_log( NULL, AV_LOG_FATAL, "Cannot find a matching stream for "
                    "unlabeled input pad %d on filter %s\n", in->pad_idx,
                    in->filter_ctx->name );
            exit( 1 );
        }
    }

    av_assert0( ist );

    ist->discard         = 0;
    ist->decoding_needed++;
    ist->st->discard = AVDISCARD_NONE;

    fg->inputs = grow_array( fg->inputs, sizeof( *fg->inputs ),
                             &fg->nb_inputs, fg->nb_inputs + 1 );

    if ( !( fg->inputs[fg->nb_inputs - 1] = av_mallocz( sizeof( *fg->inputs[0] ) ) ) )
        exit( 1 );

    fg->inputs[fg->nb_inputs - 1]->ist   = ist;
    fg->inputs[fg->nb_inputs - 1]->graph = fg;

    ist->filters = grow_array( ist->filters, sizeof( *ist->filters ),
                               &ist->nb_filters, ist->nb_filters + 1 );
    ist->filters[ist->nb_filters - 1] = fg->inputs[fg->nb_inputs - 1];
}

static int configure_output_video_filter( FilterGraph *fg, OutputFilter *ofilter, AVFilterInOut *out )
{
    char *pix_fmts;
    OutputStream *ost = ofilter->ost;
    AVCodecContext *codec = ost->st->codec;
    AVFilterContext *last_filter = out->filter_ctx;
    int pad_idx = out->pad_idx;
    int ret;
    char name[255];
    AVBufferSinkParams *buffersink_params = av_buffersink_params_alloc();

    snprintf( name, sizeof( name ), "output stream %d:%d", ost->file_index, ost->index );
    ret = avfilter_graph_create_filter( &ofilter->filter,
                                        avfilter_get_by_name( "ffbuffersink" ),
                                        name, NULL, NULL, fg->graph );
    av_freep( &buffersink_params );

    if ( ret < 0 )
        return ret;

    if ( codec->width || codec->height )
    {
        char args[255];
        AVFilterContext *filter;

        snprintf( args, sizeof( args ), "%d:%d:flags=0x%X",
                  codec->width,
                  codec->height,
                  ( unsigned )ost->sws_flags );
        snprintf( name, sizeof( name ), "scaler for output stream %d:%d",
                  ost->file_index, ost->index );

        if ( ( ret = avfilter_graph_create_filter( &filter, avfilter_get_by_name( "scale" ),
                     name, args, NULL, fg->graph ) ) < 0 )
            return ret;

        if ( ( ret = avfilter_link( last_filter, pad_idx, filter, 0 ) ) < 0 )
            return ret;

        last_filter = filter;
        pad_idx = 0;
    }

    if ( ( pix_fmts = choose_pix_fmts( ost ) ) )
    {
        AVFilterContext *filter;
        snprintf( name, sizeof( name ), "pixel format for output stream %d:%d",
                  ost->file_index, ost->index );

        if ( ( ret = avfilter_graph_create_filter( &filter,
                     avfilter_get_by_name( "format" ),
                     "format", pix_fmts, NULL,
                     fg->graph ) ) < 0 )
            return ret;

        if ( ( ret = avfilter_link( last_filter, pad_idx, filter, 0 ) ) < 0 )
            return ret;

        last_filter = filter;
        pad_idx     = 0;
        av_freep( &pix_fmts );
    }

    if ( ost->frame_rate.num && 0 )
    {
        AVFilterContext *fps;
        char args[255];

        snprintf( args, sizeof( args ), "fps=%d/%d", ost->frame_rate.num,
                  ost->frame_rate.den );
        snprintf( name, sizeof( name ), "fps for output stream %d:%d",
                  ost->file_index, ost->index );
        ret = avfilter_graph_create_filter( &fps, avfilter_get_by_name( "fps" ),
                                            name, args, NULL, fg->graph );

        if ( ret < 0 )
            return ret;

        ret = avfilter_link( last_filter, pad_idx, fps, 0 );

        if ( ret < 0 )
            return ret;

        last_filter = fps;
        pad_idx = 0;
    }

    if ( ( ret = avfilter_link( last_filter, pad_idx, ofilter->filter, 0 ) ) < 0 )
        return ret;

    return 0;
}

static int configure_output_audio_filter( FilterGraph *fg, OutputFilter *ofilter, AVFilterInOut *out )
{
    OutputStream *ost = ofilter->ost;
    AVCodecContext *codec  = ost->st->codec;
    AVFilterContext *last_filter = out->filter_ctx;
    int pad_idx = out->pad_idx;
    char *sample_fmts, *sample_rates, *channel_layouts;
    char name[255];
    int ret;


    snprintf( name, sizeof( name ), "output stream %d:%d", ost->file_index, ost->index );
    ret = avfilter_graph_create_filter( &ofilter->filter,
                                        avfilter_get_by_name( "ffabuffersink" ),
                                        name, NULL, NULL, fg->graph );

    if ( ret < 0 )
        return ret;

#define AUTO_INSERT_FILTER(opt_name, filter_name, arg) do {                 \
    AVFilterContext *filt_ctx;                                              \
                                                                            \
    av_log(NULL, AV_LOG_INFO, opt_name " is forwarded to lavfi "            \
           "similarly to -af " filter_name "=%s.\n", arg);                  \
                                                                            \
    ret = avfilter_graph_create_filter(&filt_ctx,                           \
                                       avfilter_get_by_name(filter_name),   \
                                       filter_name, arg, NULL, fg->graph);  \
    if (ret < 0)                                                            \
        return ret;                                                         \
                                                                            \
    ret = avfilter_link(last_filter, pad_idx, filt_ctx, 0);                 \
    if (ret < 0)                                                            \
        return ret;                                                         \
                                                                            \
    last_filter = filt_ctx;                                                 \
    pad_idx = 0;                                                            \
} while (0)

    if ( ost->audio_channels_mapped )
    {
        int i;
        AVBPrint pan_buf;
        av_bprint_init( &pan_buf, 256, 8192 );
        av_bprintf( &pan_buf, "0x%"PRIx64,
                    av_get_default_channel_layout( ost->audio_channels_mapped ) );

        for ( i = 0; i < ost->audio_channels_mapped; i++ )
            if ( ost->audio_channels_map[i] != -1 )
                av_bprintf( &pan_buf, ":c%d=c%d", i, ost->audio_channels_map[i] );

        AUTO_INSERT_FILTER( "-map_channel", "pan", pan_buf.str );
        av_bprint_finalize( &pan_buf, NULL );
    }

    if ( codec->channels && !codec->channel_layout )
        codec->channel_layout = av_get_default_channel_layout( codec->channels );

    sample_fmts     = choose_sample_fmts( ost );
    sample_rates    = choose_sample_rates( ost );
    channel_layouts = choose_channel_layouts( ost );

    if ( sample_fmts || sample_rates || channel_layouts )
    {
        AVFilterContext *format;
        char args[256];
        args[0] = 0;

        if ( sample_fmts )
            av_strlcatf( args, sizeof( args ), "sample_fmts=%s:",
                         sample_fmts );

        if ( sample_rates )
            av_strlcatf( args, sizeof( args ), "sample_rates=%s:",
                         sample_rates );

        if ( channel_layouts )
            av_strlcatf( args, sizeof( args ), "channel_layouts=%s:",
                         channel_layouts );

        av_freep( &sample_fmts );
        av_freep( &sample_rates );
        av_freep( &channel_layouts );

        snprintf( name, sizeof( name ), "audio format for output stream %d:%d",
                  ost->file_index, ost->index );
        ret = avfilter_graph_create_filter( &format,
                                            avfilter_get_by_name( "aformat" ),
                                            name, args, NULL, fg->graph );

        if ( ret < 0 )
            return ret;

        ret = avfilter_link( last_filter, pad_idx, format, 0 );

        if ( ret < 0 )
            return ret;

        last_filter = format;
        pad_idx = 0;
    }

    if ( audio_volume != 256 && 0 )
    {
        char args[256];

        snprintf( args, sizeof( args ), "%f", audio_volume / 256. );
        AUTO_INSERT_FILTER( "-vol", "volume", args );
    }

    if ( ( ret = avfilter_link( last_filter, pad_idx, ofilter->filter, 0 ) ) < 0 )
        return ret;

    return 0;
}

#define DESCRIBE_FILTER_LINK(f, inout, in)                         \
{                                                                  \
    AVFilterContext *ctx = inout->filter_ctx;                      \
    AVFilterPad *pads = in ? ctx->input_pads  : ctx->output_pads;  \
    int       nb_pads = in ? ctx->input_count : ctx->output_count; \
    AVIOContext *pb;                                               \
                                                                   \
    if (avio_open_dyn_buf(&pb) < 0)                                \
        exit(1);                                                   \
                                                                   \
    avio_printf(pb, "%s", ctx->filter->name);                      \
    if (nb_pads > 1)                                               \
        avio_printf(pb, ":%s", avfilter_pad_get_name(pads, inout->pad_idx));\
    avio_w8(pb, 0);                                                \
    avio_close_dyn_buf(pb, &f->name);                              \
}

int configure_output_filter( FilterGraph *fg, OutputFilter *ofilter, AVFilterInOut *out )
{
    av_freep( &ofilter->name );
    DESCRIBE_FILTER_LINK( ofilter, out, 0 );

    switch ( avfilter_pad_get_type( out->filter_ctx->output_pads, out->pad_idx ) )
    {
    case AVMEDIA_TYPE_VIDEO:
        return configure_output_video_filter( fg, ofilter, out );

    case AVMEDIA_TYPE_AUDIO:
        return configure_output_audio_filter( fg, ofilter, out );

    default:
        av_assert0( 0 );
    }
}

static int sub2video_prepare( InputStream *ist )
{
    AVFormatContext *avf = input_files[ist->file_index]->ctx;
    int i, ret, w, h;
    uint8_t *image[4];
    int linesize[4];

    /* Compute the size of the canvas for the subtitles stream.
       If the subtitles codec has set a size, use it. Otherwise use the
       maximum dimensions of the video streams in the same file. */
    w = ist->st->codec->width;
    h = ist->st->codec->height;

    if ( !( w && h ) )
    {
        for ( i = 0; i < avf->nb_streams; i++ )
        {
            if ( avf->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO )
            {
                w = FFMAX( w, avf->streams[i]->codec->width );
                h = FFMAX( h, avf->streams[i]->codec->height );
            }
        }

        if ( !( w && h ) )
        {
            w = FFMAX( w, 720 );
            h = FFMAX( h, 576 );
        }

        av_log( avf, AV_LOG_INFO, "sub2video: using %dx%d canvas\n", w, h );
    }

    ist->sub2video.w = ist->st->codec->width  = w;
    ist->sub2video.h = ist->st->codec->height = h;

    /* rectangles are AV_PIX_FMT_PAL8, but we have no guarantee that the
       palettes for all rectangles are identical or compatible */
    ist->st->codec->pix_fmt = AV_PIX_FMT_RGB32;

    ret = av_image_alloc( image, linesize, w, h, AV_PIX_FMT_RGB32, 32 );

    if ( ret < 0 )
        return ret;

    memset( image[0], 0, h * linesize[0] );
    ist->sub2video.ref = avfilter_get_video_buffer_ref_from_arrays(
                             image, linesize, AV_PERM_READ | AV_PERM_PRESERVE,
                             w, h, AV_PIX_FMT_RGB32 );

    if ( !ist->sub2video.ref )
    {
        av_free( image[0] );
        return AVERROR( ENOMEM );
    }

    return 0;
}

static int configure_input_video_filter( FilterGraph *fg, InputFilter *ifilter,
        AVFilterInOut *in )
{
    AVFilterContext *first_filter = in->filter_ctx;
    AVFilter *filter = avfilter_get_by_name( "buffer" );
    InputStream *ist = ifilter->ist;
    AVRational tb = ist->framerate.num ? av_inv_q( ist->framerate ) :
                    ist->st->time_base;
    AVRational fr = ist->framerate.num ? ist->framerate :
                    ist->st->r_frame_rate;
    AVRational sar;
    AVBPrint args;
    char name[255];
    int pad_idx = in->pad_idx;
    int ret;

    if ( !ist->framerate.num && ist->st->codec->ticks_per_frame > 1 )
    {
        AVRational codec_fr = av_inv_q( ist->st->codec->time_base );
        codec_fr.den *= ist->st->codec->ticks_per_frame;

        if ( codec_fr.num > 0 && codec_fr.den > 0 && av_q2d( codec_fr ) < av_q2d( fr ) * 0.7 )
            fr = codec_fr;
    }

    if ( ist->st->codec->codec_type == AVMEDIA_TYPE_SUBTITLE )
    {
        ret = sub2video_prepare( ist );

        if ( ret < 0 )
            return ret;
    }

    sar = ist->st->sample_aspect_ratio.num ?
          ist->st->sample_aspect_ratio :
          ist->st->codec->sample_aspect_ratio;

    if ( !sar.den )
    {
        sar.num = 0;
        sar.den = 1;
    }

    av_bprint_init( &args, 0, 1 );
    av_bprintf( &args,
                "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:"
                "pixel_aspect=%d/%d:sws_param=flags=%d", ist->st->codec->width,
                ist->st->codec->height, ist->st->codec->pix_fmt,
                tb.num, tb.den, sar.num, sar.den,
                SWS_BILINEAR + ( ( ist->st->codec->flags & CODEC_FLAG_BITEXACT ) ? SWS_BITEXACT : 0 ) );

    if ( fr.num && fr.den )
        av_bprintf( &args, ":frame_rate=%d/%d", fr.num, fr.den );

    snprintf( name, sizeof( name ), "graph %d input from stream %d:%d", fg->index,
              ist->file_index, ist->st->index );

    if ( ( ret = avfilter_graph_create_filter( &ifilter->filter, filter, name,
                 args.str, NULL, fg->graph ) ) < 0 )
        return ret;

    if ( ist->framerate.num )
    {
        AVFilterContext *setpts;

        snprintf( name, sizeof( name ), "force CFR for input from stream %d:%d",
                  ist->file_index, ist->st->index );

        if ( ( ret = avfilter_graph_create_filter( &setpts,
                     avfilter_get_by_name( "setpts" ),
                     name, "N", NULL,
                     fg->graph ) ) < 0 )
            return ret;

        if ( ( ret = avfilter_link( setpts, 0, first_filter, pad_idx ) ) < 0 )
            return ret;

        first_filter = setpts;
        pad_idx = 0;
    }

    if ( ( ret = avfilter_link( ifilter->filter, 0, first_filter, pad_idx ) ) < 0 )
        return ret;

    return 0;
}

static int configure_input_audio_filter( FilterGraph *fg, InputFilter *ifilter,
        AVFilterInOut *in )
{
    AVFilterContext *first_filter = in->filter_ctx;
    AVFilter *filter = avfilter_get_by_name( "abuffer" );
    InputStream *ist = ifilter->ist;
    int pad_idx = in->pad_idx;
    char args[255], name[255];
    int ret;

    snprintf( args, sizeof( args ), "time_base=%d/%d:sample_rate=%d:sample_fmt=%s"
              ":channel_layout=0x%"PRIx64,
              1, ist->st->codec->sample_rate,
              ist->st->codec->sample_rate,
              av_get_sample_fmt_name( ist->st->codec->sample_fmt ),
              ist->st->codec->channel_layout );
    snprintf( name, sizeof( name ), "graph %d input from stream %d:%d", fg->index,
              ist->file_index, ist->st->index );

    if ( ( ret = avfilter_graph_create_filter( &ifilter->filter, filter,
                 name, args, NULL,
                 fg->graph ) ) < 0 )
        return ret;

#define AUTO_INSERT_FILTER_INPUT(opt_name, filter_name, arg) do {                 \
    AVFilterContext *filt_ctx;                                              \
                                                                            \
    av_log(NULL, AV_LOG_INFO, opt_name " is forwarded to lavfi "            \
           "similarly to -af " filter_name "=%s.\n", arg);                  \
                                                                            \
    snprintf(name, sizeof(name), "graph %d %s for input stream %d:%d",      \
                fg->index, filter_name, ist->file_index, ist->st->index);   \
    ret = avfilter_graph_create_filter(&filt_ctx,                           \
                                       avfilter_get_by_name(filter_name),   \
                                       name, arg, NULL, fg->graph);         \
    if (ret < 0)                                                            \
        return ret;                                                         \
                                                                            \
    ret = avfilter_link(filt_ctx, 0, first_filter, pad_idx);                \
    if (ret < 0)                                                            \
        return ret;                                                         \
                                                                            \
    first_filter = filt_ctx;                                                  \
} while (0)

    if ( audio_sync_method > 0 )
    {
        char args[256] = {0};

        av_strlcatf( args, sizeof( args ), "min_comp=0.001:min_hard_comp=%f", audio_drift_threshold );

        if ( audio_sync_method > 1 )
            av_strlcatf( args, sizeof( args ), ":max_soft_comp=%f", audio_sync_method / ( double )ist->st->codec->sample_rate );

        AUTO_INSERT_FILTER_INPUT( "-async", "aresample", args );
    }

//     if (ost->audio_channels_mapped) {
//         int i;
//         AVBPrint pan_buf;
//         av_bprint_init(&pan_buf, 256, 8192);
//         av_bprintf(&pan_buf, "0x%"PRIx64,
//                    av_get_default_channel_layout(ost->audio_channels_mapped));
//         for (i = 0; i < ost->audio_channels_mapped; i++)
//             if (ost->audio_channels_map[i] != -1)
//                 av_bprintf(&pan_buf, ":c%d=c%d", i, ost->audio_channels_map[i]);
//         AUTO_INSERT_FILTER_INPUT("-map_channel", "pan", pan_buf.str);
//         av_bprint_finalize(&pan_buf, NULL);
//     }

    if ( audio_volume != 256 )
    {
        char args[256];

        snprintf( args, sizeof( args ), "%f", audio_volume / 256. );
        AUTO_INSERT_FILTER_INPUT( "-vol", "volume", args );
    }

    if ( ( ret = avfilter_link( ifilter->filter, 0, first_filter, pad_idx ) ) < 0 )
        return ret;

    return 0;
}

static int configure_input_filter( FilterGraph *fg, InputFilter *ifilter,
                                   AVFilterInOut *in )
{
    av_freep( &ifilter->name );
    DESCRIBE_FILTER_LINK( ifilter, in, 1 );

    switch ( avfilter_pad_get_type( in->filter_ctx->input_pads, in->pad_idx ) )
    {
    case AVMEDIA_TYPE_VIDEO:
        return configure_input_video_filter( fg, ifilter, in );

    case AVMEDIA_TYPE_AUDIO:
        return configure_input_audio_filter( fg, ifilter, in );

    default:
        av_assert0( 0 );
    }
}

int configure_filtergraph( FilterGraph *fg )
{
    AVFilterInOut *inputs, *outputs, *cur;
    int ret, i, init = !fg->graph, simple = !fg->graph_desc;
    const char *graph_desc = simple ? fg->outputs[0]->ost->avfilter :
                             fg->graph_desc;

    avfilter_graph_free( &fg->graph );

    if ( !( fg->graph = avfilter_graph_alloc() ) )
        return AVERROR( ENOMEM );

    if ( simple )
    {
        OutputStream *ost = fg->outputs[0]->ost;
        char args[255];
        snprintf( args, sizeof( args ), "flags=0x%X", ( unsigned )ost->sws_flags );
        fg->graph->scale_sws_opts = av_strdup( args );
    }

    if ( ( ret = avfilter_graph_parse2( fg->graph, graph_desc, &inputs, &outputs ) ) < 0 )
        return ret;

    if ( simple && ( !inputs || inputs->next || !outputs || outputs->next ) )
    {
        av_log( NULL, AV_LOG_ERROR, "Simple filtergraph '%s' does not have "
                "exactly one input and output.\n", graph_desc );
        return AVERROR( EINVAL );
    }

    for ( cur = inputs; !simple && init && cur; cur = cur->next )
        init_input_filter( fg, cur );

    for ( cur = inputs, i = 0; cur; cur = cur->next, i++ )
        if ( ( ret = configure_input_filter( fg, fg->inputs[i], cur ) ) < 0 )
            return ret;

    avfilter_inout_free( &inputs );

    if ( !init || simple )
    {
        /* we already know the mappings between lavfi outputs and output streams,
         * so we can finish the setup */
        for ( cur = outputs, i = 0; cur; cur = cur->next, i++ )
            configure_output_filter( fg, fg->outputs[i], cur );

        avfilter_inout_free( &outputs );

        if ( ( ret = avfilter_graph_config( fg->graph, NULL ) ) < 0 )
            return ret;
    }
    else
    {
        /* wait until output mappings are processed */
        for ( cur = outputs; cur; )
        {
            fg->outputs = grow_array( fg->outputs, sizeof( *fg->outputs ),
                                      &fg->nb_outputs, fg->nb_outputs + 1 );

            if ( !( fg->outputs[fg->nb_outputs - 1] = av_mallocz( sizeof( *fg->outputs[0] ) ) ) )
                exit( 1 );

            fg->outputs[fg->nb_outputs - 1]->graph   = fg;
            fg->outputs[fg->nb_outputs - 1]->out_tmp = cur;
            cur = cur->next;
            fg->outputs[fg->nb_outputs - 1]->out_tmp->next = NULL;
        }
    }

    return 0;
}

int ist_in_filtergraph( FilterGraph *fg, InputStream *ist )
{
    int i;

    for ( i = 0; i < fg->nb_inputs; i++ )
        if ( fg->inputs[i]->ist == ist )
            return 1;

    return 0;
}

